The advent of the ubiquitous era has allowed access to information at any time in any place. Further, digital convergence technology, in which computers, communication and electronic instruments, etc., are fused and combined, is being rapidly developed. Thus, displays serving as interfaces between electronic instruments and humans are becoming more important. In place of bulky and heavy Cathode Ray Tubes (CRTs), displays have been developed in the form of flat and lightweight Flat Panel Displays (FPDs) However, the FPDs employ glass substrates to overcome extreme heat generated during fabricating processes. For this reason, there is a limit to which the FPDs can be made light, thin and flexible. Thus, by using flexible materials such as plastic in place of the inflexible glass substrates, flexible displays, which are capable of maintaining display performance even when bent or curved, like paper, have been developed and are emerging as next generation displays.